MIAMI (AFP) - Serena and Venus Williams plan to play for the US Fed Cup team in a World Group play-off tie next month against Italy.

Italy will host the best-of-five match tie on a clay court in Brindisi on April 18-19.

The two nations are fighting for a place in the tournament's top tier.

"We deserve to be back in," Serena said on Saturday as she opened her title defence at the Miami Open.

"We have some of the best players in the world. We should be in the World Group A and competing for the title."

The US dropped out of the World Group in 2014.

Italy, meanwhile, are facing relegation for the first time since 2008 after winning the title in 2009, 2010 and 2013.

Led by the Williams sisters, the USA beat Argentina 4-1 in Buenos Aires last month to advance to the play-off round with a chance to return to the World Group in 2016.

The US have won the Fed Cup 17 times but their most recent triumph was in 2000.