The International Cricket Council has warned Sri Lanka's Board of Control that it must return completed World Cup player contracts by Friday or face 'serious consequences.'

'The IDI (world cricket body's marketing arm) confirmed today that it is expecting to receive the signed player terms from the BCCSL tomorrow (Friday),' ICC chief executive Malcolm Speed said in a statement on Thursday.

'We have been in regular contact with the BCCSL and expect to receive the signed player terms on Friday,' he added.

'Failure to return the contracts will have very serious consequences for the BCCSL.'

The player contracts were supposed to have been delivered to the ICC two days ago.

Earlier, cricket web site cricinfo.com reported the Sri Lankans had refused to sign their contracts because of an argument about payments.

The web site said a statement from the Sri Lanka Cricketers Association said: 'The SLCA confirms that the controversial players' terms agreement has not been signed by the Sri Lanka players.'

The Association said it was demanding the BCCSL paid their players 20 percent of the revenue they receive from the World Cup, which is due to begin in southern Africa on February 9. The SLCA said players had been offered only five percent.

'The players of Australia and New Zealand are being paid 25 percent...the South Africans are almost there with 30 percent of the total money received from their board,' the SLCA statement added.

'In view of the above, the 20 percent that the Sri Lankan players are requesting seems reasonable enough.'

The dispute is another problem for the ICC after the Indian team returned signed, but 'altered' contracts on Tuesday.

The Indian players have been involved in a long-standing dispute with the ICC over image rights and personal advertising contracts that might clash with official World Cup sponsors.