Watford have told Newcastle they must improve their £2m offer for Adrian Mariappa, according to the Daily Mail.
Magpies boss Alan Pardew is one of a number of Premier League managers interested in signing the powerful 25-year-old defender, with Swansea and Bolton also circling.
Newcastle's first offer of £2m was quickly rejected by the Championship club but the Hornets could be willing to do business at £4m, with the player said to be keen on a move to the Premier League.
Mariappa has appeared 231 times for Watford since joining the first team in 2005.
