The European Central Bank is actively buying government bonds in the secondary market, ECB President Jean-Claude Trichet said on Tuesday, urging governments to implement new measures agreed at July 21 crisis talks quickly.

Asked by Europe 1 radio how long the ECB will stay in the secondary market Trichet said: Obviously I will not tell you, but he said bond-buying was an effective way of restoring stability by transmitting the bank's interest rate decisions through to markets.

We are in the secondary market. I will not tell you moreover what we are buying ... or the amount, but the amounts are known of course and in that sense we are totally transparent, Trichet said.

For a long time now, since May 2010, we effectively have a new measure, an unconventional measure, which allows us to try to better ensure this transmission (of monetary policy decisions), he said.

The ECB stepped in to markets on Monday to buy Italian and Spanish bonds, forcing down borrowing costs for the two states now at the center of the euro zone's debt crisis after a weekend of emergency talks between G7 and G20 leaders.

What we have is a problem of confidence at the moment in the international economy, said Trichet, who urged euro zone governments to do their part in getting parliaments to approve decisions taken on July 21 on new emergency bailout powers.

What we need is for governments to do what we consider to be their job, he said. What we ask is that all the decisions which were taken on July 21 be put into effect as quickly as possible.

(Reporting by Alexandria Sage and Nick Vinocur; editing by Patrick Graham)