'Once the diplomatic issues [between China and the Vatican] are settled, a lot of problems will be solved easily,' Bishop Zhan said on the sidelines of the Chinese People's Political Consultative Conference, of which he is a delegate.

In sharp contrast to the association's usual hardline approach that the mainland church has the sole power to select and appoint bishops on the mainland, Bishop Zhan said: 'The most important issue is for bishops to remain in close communion with the Holy Father. That means when a bishop is ordained, he should have received papal endorsement.'

The issue of bishops' appointments, along with the Taiwan issue, has remained a thorny subject between Beijing and the Holy See despite quiet and circuitous attempts by the two sides towards normalising ties that were cut after 1949.

There have been calls to take into consideration the so-called 'Vietnamese model' - whereby the Vatican proposes several bishop candidates for the government to choose from before Pope Benedict gives his final approval - with Hong Kong Catholic leader Cardinal Joseph Zen Ze-kiun as one of the advocates. Beijing-backed newspapers have also quoted unnamed mainland sources as saying the model could be a reference.

The flexible Vietnamese policy has greatly improved ties between Hanoi and the Vatican, leading to the first meeting in 30 years between a Vietnamese communist leader and the Pope in January this year.

But Bishop Zhan, who is one of the younger of the official church's influential leaders, said it was not realistic to copy that model in China. 'The Vietnam model can be a reference. But since situations in China and Vietnam are different, I don't think it's feasible to adopt the model in China,' he said.

Beijing has been accused of unilaterally appointing bishops in a bid to maintain its authority over the church. Last year, three bishops were ordained without Vatican approval.

Bishop Zhan is among the five bishops appointed in 2000 by Beijing without Vatican approval in a move to counter a Vatican decision to canonise 120 Chinese martyrs. Last week, the director of the State Bureau of Religious Affairs, Ye Xiaowen , said the Vatican had not done enough to improve relations, outlining two principles to which it has not adhered - that the Vatican acknowledge Taiwan as a part of the mainland and not intervene in China's domestic affairs.

Mr Ye's remark follows reports that the Pope is expected to issue an open letter to the mainland's 12 million Catholics around Easter next month.

Beijing is keenly awaiting the letter, which is expected to contain a firm reiteration of the church's right to appoint bishops and give directions on the relationship between Catholics and the Chinese Patriotic Catholic Association.

Appointed in May last year, Bishop Zhan's appointment has yet to be approved by the Holy See although he has applied for this.

Bishop Zhan said the earlier high-level meeting on China at the Vatican and the Pope's forthcoming Easter letter were signs of improving relations between the two sides.

The bishop said it was necessary to establish a 'special and direct channel' to avoid any 'outside obstructions', a term he refused to elaborate on. 'And it will be best if such a channel is at a diplomatic level,' he said.

Bishop Zhan said he hoped the Pope's letter would encourage the unification of government-sanctioned churches with underground ones.

Although most of the bishops in the official church also are recognised by the Vatican, a sizeable number of Catholics remain in the so-called underground church loyal to the Pope because they consider the patriotic association, which runs church affairs, as illicit.