Polls have opened in the Greece bailout referendum, as voters decide whether to accept a deal offered by the country's creditors, Sky News reported Sunday.

Opinion polls suggest the "Yes" and "No" camps are neck-and-neck.

Prime Minister Alexis Tsipras, who cast his vote this morning in front of dozens of photographers, has insisted a No vote would allow his government to push for a better bailout package.

The premier has strongly indicated he will step down if the Greek people back the terms offered by the EU, the IMF and the European Central Bank.