Greece is likely to reach a draft deal with creditor banks on writing off half of its debt by the beginning of January, a Greek government source said on Tuesday. \"The framework of the negotiations... is advancing well, there is no agreement at the moment, it is probable that by the beginning of January there will be a draft agreement,\" said the source who declined to be named. The overall operation must be completed by the end of January, the source said. The negotiations began in November and are intended to work out the details of how the banks will write off 100 billion euros\' ($130 billion) worth of the debt owed by Greece which totals about 350 billion euros. The banks agreed to a write-down of about 50 percent of the value of the Greek bonds they own, under pressure from a eurozone summit meeting at the end of October. Since then European Union leaders have made clear that banks will not be pressed again to take a write-down or so-called \"haircut\" on the value of their loans. Suggestions from Germany at the beginning of the year that in future private bondholders should expect to bear part of the cost of rescuing countries in trouble over their public finances contributed to fast-rising tension on the eurozone bond market. Some governments have since encountered increased and severe problems in raising money to fund their public deficits and debt. The talks between Greece and the banks involve replacing bonds held by the banks with new bonds in such a way as to reduce the debt burden from 160 percent of gross domestic product to 120 percent in 2020. The government has described the negotiations as \"difficult and complicated\". Points at issue concern the percentage repayment loss to be suffered by the banks, on the interest rate to be paid on the new bonds, and on the nationality of the law applying to the new instruments. Some Greek media reported on Tuesday that the talks might be heading towards a write-down of 65 percent by the banks, and an interest rate of about 4.0 percent, with 100-percent participation by private holders of bonds. However, no official comment was available on this. On Friday, the Institute of International Finance representing creditor banks in the negotiations said that \"progress\" had been made. The bond rollover was part of a package of measures agreed at the October summit which also involved a loan of 100 billion euros from eurozone countries, and 30 billion euros to recapitalise Greek banks which hold nearly 50 billion euros\' worth of Greek debt.