Former US President George H W Bush, admitted to a hospital after experiencing shortness of breath, was in "great spirits," his spokesman said today.

90-year-old Bush, a Texas resident, was admitted to Houston Methodist Hospital on Tuesday as a precaution. His spokesman Jim McGrath said that the 41st president's prognosis was positive and that he remained hospitalised as a precaution.

"President Bush had another terrific day and is in great spirits," McGrath said in an emailed statement.

Bush's wife, Barbara, as well as son Neil and daughter- in-law Maria Bush visited the former president, McGrath said. "He asked that his sincere wishes for a very Merry Christmas be extended to one and all," McGrath said, adding that Bush will remain at the hospital.