LONDON—The Greek government’s offering for a 10-year bond attracted around €14.5 billion ($19.86 billion) in bids and the books have closed, the head of the country’s debt-management agency said Thursday.

“We are very happy with the bid because the re-entry into the market is always challenging. It went very well,” Petros Christodoulou said. The government aimed to raise €5 billion from the offering but it was heavily oversubscribed.

The offering—timed to coincide with an improving market for Greek government debt in the wake of tough budget cuts announced a day earlier—is a move to help cover short-term funding gaps.

Lead managers are Barclays Capital, HSBC Holdings, National Bank of Greece, Nomura and Piraeus Bank SA, one of the lead managers on the deal said.

Adjusted price guidance for the new issue is now 3.00 percentage points over the benchmark risk-free mid-swaps rate, reflecting the market’s demand for a premium.

An issue size of €5 billion for Greece’s new 10-year bond “would be a good result” but not enough to fully cover Greece’s near-term funding needs, said UniCredit strategist Luca Cazzulani.

Greek bond yields in secondary markets moved up on the news. The yield spread between Greek 10-year government bonds over equivalent German government bonds widened to around 3.03 percentage points from Wednesday’s close at 2.92 percentage points.

The cost of insuring Greek sovereign debt against default also rose slightly. The price of Greece’s five-year sovereign credit default swaps increased to 3.05 percentage points, from 2.945 percentage points, representing a €10,500 increase in the annual cost of insuring €10 million of debt for five years.

Greece, the European Union’s most indebted country, will face its biggest challenge in April and May this year, when more than €20 billion of debt comes due for repayment. So far, Greece has raised €13.6 billion via the sale of Treasury bills and an €8 billion bond syndication, the Public Debt Management Agency said. Greece plans to issue a total of €54 billion in debt this year.

While Greece has been encouraged by its ability so far to raise funds from public markets, the cost of issuing new bonds remains high. The yield on 10-year Greek government bonds has risen to as high as 3.40 percentage points over equivalent German bunds, from low-double-digits before the start of the financial crisis.

Greece’s latest set of spending cuts and tax increases aims to cut the country’s gaping budget deficit by €4.8 billion or about 2% of gross domestic product, and follows pressure from the European Commission, the EU’s executive arm, which said last week that Greece’s previously announced measures weren’t tough enough.

Greek officials worry that its budget cuts won’t be enough to restore investor confidence in Greek debt unless the government receives detailed financial backing from the European Union.

Greek Finance Minister George Papaconstantinou said in Athens Wednesday that if Greece can’t rule out turning to the International Monetary Fund for assistance if Greece needs help and euro-zone partners won’t give it.

IMF financing would need approval by European countries on the IMF’s board. Most euro-zone governments have made clear they want a European solution to the Greek crisis rather than IMF intervention, to show the euro zone can handle its own problems.

Greece is rated A2 by Moody’s Investors Service and BBB+ by Standard & Poor’s Corp. and Fitch Ratings Inc.