Ai Weiwei has handed $1.3 million in donations from his supporters to the Chinese authorities to clear the way for an appeal against a huge tax bill, a lawyer for the artist and activist said Tuesday.

Ai, 54, had been given until Wednesday to settle a 15 million yuan ($2.4 million) bill for alleged unpaid taxes levied against a company he has links to after he was released from 81 days in secret police detention this year.

The artist maintains the government's charge that he evaded taxes for years is a politically-motivated attempt to silence his vocal human rights activism, and has vowed to challenge it.

Xia Ling, a lawyer for the company, said Ai had reluctantly handed over the 8.45 million yuan ($1.3 million) donated by supporters, who came from far and wide to help him raise cash after news of the massive tax bill emerged.

He insists Ai has no legal involvement in Beijing Fake Cultural Development, the company accused of evading taxes. The money paid Tuesday is only a bond that clears the way for an appeal.

"This morning, the tax bureau spoke to us and they clearly insisted that we had to transfer the money to the account they designated, that it was the only solution and the company had to accept it," he told AFP.

The tax bureau, he added, assured them that "this sum of money will be the payment for the guarantee, and not the tax itself".

Earlier Tuesday, Ai said tax officials were threatening to "kick the ball to the police" if the issue was not settled by the Wednesday deadline.

They had turned down his offer to provide proof he held the collateral in a bank account and insisted it be paid directly to them, he said.

Xia said that if all goes to plan, Ai and his team of lawyers now have two months to prepare an appeal against the tax bill.

The artist, best known in China for his role in designing Beijing's "Bird's Nest" Olympic stadium, has denied any wrongdoing.

His case is particularly complicated because he founded Beijing Fake Cultural Development, but his wife owns the company.

He has said he will pay back his supporters once the case is over, and was initially reluctant to hand over the money raised to Chinese authorities for fear that it would not be returned to him.

Ai is known for his often irreverent art and for tallying the children killed in the 2008 Sichuan earthquake, shining an unflattering light on officials who some accused of covering up the role shoddy housing played in the deaths.

Over the past week, some 30,000 supporters have donated money through Internet and bank transfers, while some even threw cash over the walls into his courtyard home, including banknotes folded into paper planes.

Total donations had reached 8.69 million yuan ($1.4 million) by Sunday night, when the appeal closed, according to Ai.

Chinese tax authorities have repeatedly refused AFP's requests for comment on the case.